1. Field of the Invention
The present invention relates to a transportation container for housing precision substrates typified by semiconductor wafers such as silicon wafers, and a method for opening and closing a lid thereof.
2. Description of the Prior Art
Examples of the types of containers for precision substrates such as semiconductor wafers include process cassettes, open cassettes, production containers used in the carrying of precision substrates within a clean room, and third cassettes, as well as transportation containers used for movement between factories and for shipping
Transportation containers of the prior art, as shown in FIG. 1 for example, are configured from a rectangular container body 140 with base, an inner box 141 which is housed within this container body 140 in which a plurality of precision substrates are housed in a row arrangement, a cushon member 142 which contacts the upper end of the plurality of precision substrates, and a freely detachable lid 144 which closes up, by way of a frame-form packing 143, the open upper part of the container body 140. Outward projecting clamp members 145 are arranged in both the left and right sides of the open upper part of the container body 140, and elastic hooks 146 with clamp holes, which fit over the clamp members 145, are arranged in both the left and right sides of the lid 144, and the closed state of the lid 144 with respect to the container body 140 is maintained by virtue of the engagement between the clamp members 145 and the elastic hooks 146. There is a strong demand in transportation containers such as this for, in particular, sealing characteristics, to prevent contamination of the plurality of precision substrates, and for safety, in order to prevent breakage of the precision substrates.
In the field of manufacturing semiconductors, studies have been conducted enthusiastically, aiming at increase in diameter of precision substrate which is demanded as a result of increased size of chips (for example, in semiconductor wafers, from 200 mm to 300 mm), decreasing contamination, and improving the degree of cleanliness of the clean room. In order to realize these objects, automation of related equipment is indispensable. This is because, when the diameter of the precision substrates is increased, the size of containers for housing them is also enlarged, and the weight is thereby increased, whereby the works of operators approximates ergonomics upper limits to make automation of such works necessary. In addition, the works must be automated also because the operators themselves constitute a source of contaminant in the attempts to control contamination of precision substrates and to improve the degree of cleanliness.
In recent years, while attending to the prevention of environmental damages and placing importance on standardization and normalization, researches have been conducted all over the world in order to realize highly automated next-generation semiconductor factories, manufacturing devices, processes, systems, SMIFs (Standard Mechanical Interface) and the like. As a part of these, exhaustive researches have been carried out also on sealed containers for precision substrates, and specific developments, in particular in production containers, are being made.
This type of production containers are known as FOUP (Front Opening Unified Pod) which are, although not shown in the drawings, composed of a container body formed in a front opening box structure, and a lid which opens and closes the open front face of the container body, configured such that they can be connected directly to a substrate processing device, and used as conveyance carriers between processes. A pair of elastic retainers are provided on the interior back face of the container body and on the opposing face of the lid, respectively, to contact and support the outer circumferential edges of the precision substrates. These retainers hold the precision substrates to ensure safety. In addition, a mechanical latching mechanism, which is automatically operated by an automaton machine, is built into the lid, and this mechanical latching mechanism having a large number of components maintains the closed state of the lid with respect to the container body.
Examples of related prior art documents include Japanese Utility Model Application Laid-open Hei 7 No. 29841, and Japanese Patent Application Laid-open Hei 8 No. 279564 and Hei 9 No. 107025. As mentioned in the above, automation is progressing with respect to the production containers for precision substrates, and there is a strong demand for transportation containers of an automation type. In particular, realization of transportation containers that can be used with a degree of cleanliness of less than 1 is strongly expected. Under such circumstances, some extent of standardization and normalization are being carried out also on transportation containers, in other words, FOSBs (Front Opening Shipping Boxes).
However, transportation containers, unlike production containers, require higher sealability and safety in order to cope with harsh transportation conditions as well as the problem of dust invading into the container as a result of pressure fluctuations during air transport, and therefore the clamp members 145 and elastic hooks 146 must be engaged very firmly. Consequently, the operability of the clamp members 145 and elastic hooks 146 is retarded to require very delicate adjustment of force to be used in opening and closing the lid 144, and such work must be done manually by an operator. Further, because the engagement configuration between the clamp members 145 and elastic hooks 146 is complicated, automation of the opening and closing of the lid 144 is very difficult. Still further, unlike the production containers which can be manufactured in relatively small quantity, the transportation containers need to be manufactured in mass, and therefore low cost manufacturing is imperative.
As a method for resolving drawbacks mentioned above and realizing automatic handling of transportation containers, configuration of production containers may be applied to transportation containers. However, in contrast to transportation containers which are designed with much emphasis on strength, production containers are designed as carriers to afford the smooth execution of operations within a factory. Thus, the designing concepts are basically different between these two types of containers and, therefore, those production containers are not suitable for application into transportation containers in view of sealability, safety and durability. In particular, the adoption of a mechanical latching mechanism comprising a plurality of components results in complexity of configuration and cost increase, which constitutes a large impediment to cost reduction.
The present invention is made with respect to the above-mentioned drawbacks and is directed to provide a transportation container and a method for opening and closing a lid thereof, which are suitable for automation process with good sealability, safety and durability.
In order to achieve the above-mentioned object, the subject matters of the present invention are as follows.
According to a first aspect of the present invention, a transportation container comprises: a container body for housing precision substrates; a detachable lid adapted to engage in and cover an open end face of the container body via a seal gasket, and a locking mechanism adapted to fix the lid engaged into the open end face of the container body, wherein the locking mechanism having a pair of protrusions formed at the opposing sides of a rim of the open end face of the container body, and having a pair of clamp plates which are swingably journaled on opposing sides of the lid to clamp the protrusions, each protrusion having, on the back thereof, a groove to be clamped, each clamp plate having attachment shafts for the lid formed in one end of the clamp plate and operated parts for automatic operation formed in the other end, each clamp plate being provided with an approximately U-shaped groove holes to be fitted with the protrusion, thereby a clamping piece of an approximately rectangular shape to be inserted and fitted in the clamping groove, such that it can be bent in the thickness direction of the clamp plate.
According to a second aspect of the present invention, the transportation container as defined in the first aspect further comprises: each clamp plate is formed with a synthetic resin and at least a part of the other end of the clamp plate is bent in the direction either toward the front or the back side of the clamp plate to form the operated parts, one or more rotation-restricting projections being provided around the attachment shaft.
According to a third aspect of the present invention, the transportation container as defined in the first aspect further comprises: a bottom plate, made of a synthetic resin such as polycarbonate, is detachably disposed to the center of the base of the container body.
According to a fourth aspect of the present invention, the transportation container as defined in the first aspect further comprises: a positioning member with a cross section of approximately inverse V-shape is arranged at the base of the container body.
According to a fifth aspect of the present invention, the transportation container as defined in the first aspect further comprises: a plurality of housing grooves having a cross section of laid-down U-shape are vertically arranged in parallel in the opposing left and right sides inside the container body.
According to a sixth aspect of the present invention, the transportation container as defined in the first aspect further comprises: the attachment shafts for the clamp plates are fixed to the opposing sides of the lid, and swinging hinges are formed linearly along the interface of the clamp plates and attachment shafts in such a way that the clamp plates are able to swing around them.
According to a seventh aspect of the present invention, a method for opening and closing a lid of a transportation container comprises: the transportation container comprising; a container body for housing precision substrates, a detachable lid adapted to engage in and cover an open end face of the container body via a seal gasket, and a locking mechanism adapted to fix the lid engaged into the open end face of the container body, wherein the locking mechanism having a pair of protrusions formed at the opposing sides of a rim of the open end face of the container body, and having a pair of clamp plates which are swingably journaled on opposing sides of the lid to clamp the protrusions, each protrusion having, on the back thereof, a groove to be clamped, each clamp plate having attachment shafts for the lid formed in one end of the clamp plate and operated parts for automatic operation formed in the other end, each clamp plate being provided with an approximately U-shaped groove holes to be fitted with the protrusion, thereby a clamping piece of an approximately rectangular shape to be inserted and fitted in the clamping groove, such that it can be bent in the thickness direction of the clamp plate; a transportation mechanism for moving a mounting base for mounting the container body of the transportation container back and forth between an operating region and a supply/discharge region; a plurality of positioning members for positioning the container body on the mounting base; a lift mechanism adapted to move up and down a support base between the operation region and a siding region; a clamp mechanism mounted on the support base of the lift mechanism to hold the lid; and operation mechanisms mounted on opposing sides of the support base, the operation mechanisms being adapted to allow the clamp plates of the locking mechanism to swing into a release position where the lid can be removed from the container body from the state engaged with the open end face of the container body, the operation mechanisms being also adapted to allow the clamp plates of the locking mechanism to swing into a close position where the lid is fixed to the open end face of the container body, wherein the method comprising: positioning and mounting the container body on the mounting base of the transportation mechanism through a plurality of positioning members; lifting the support base of the lift mechanism from the siding region to the operation region; advancing the mounting base of the transportation mechanism from a supply/discharge region to the operation region to hold the lid by the clamp mechanisms; swinging the clamp plates into the release position where the lid can be removed; retracting the mounting base from the operation region to the supply/discharge region to separate the lid from the container body; and lowering the support base from the operation region to the siding region.
According to an eighth aspect of the present invention, a method for opening and closing a lid of a transportation container comprises: a transportation container comprising; a container body for housing precision substrates, a detachable lid adapted to engage in and cover an open end face of the container body via a seal gasket, and a locking mechanism adapted to fix the lid engaged into the open end face of the container body, wherein the locking mechanism having a pair of protrusions formed at the opposing sides of a rim of the open end face of the container body, and having a pair of clamp plates which are swingably journaled on opposing sides of the lid to clamp the protrusions, each protrusion having, on the back thereof, a groove to be clamped, each clamp plate having attachment shafts for the lid formed in one end of the clamp plate and operated parts for automatic operation formed in the other end, each clamp plate being provided with an approximately U-shaped groove holes to be fitted with the protrusion, thereby a clamping piece of an approximately rectangular shape to be inserted and fitted in the clamping groove, such that it can be bent in the thickness direction of the clamp plate; a transportation mechanism for moving a mounting base for mounting the container body of the transportation container back and forth between an operating region and a supply/discharge region; a plurality of positioning members for positioning the container body on the mounting base; a lift mechanism adapted to move up and down a support base between the operation region and a siding region; a clamp mechanism mounted on the support base of the lift mechanism to hold the lid; and operation mechanisms mounted on opposing sides of the support base, the operation mechanisms being adapted to allow the clamp plates of the locking mechanism to swing into a release position where the lid can be removed from the container body from the state engaged with the open end face of the container body, the operation mechanisms being also adapted to allow the clamp plates of the locking mechanism to swing into a close position where the lid is fixed to the open end face of the container body, in which the lid previously held by the clamp mechanism being engaged and fixed in the container body positioned and mounted on the mounting base through a plurality of positioning members, the method comprising:
lifting the support base of the lift mechanism from the siding region to the operation region to position the lid in the operation region; advancing the mounting base of the transportation mechanism from a supply/discharge region to the operation region to engage the lid with the open end face of the container body; swinging the clamp plates of the locking mechanism, by the operation mechanism, to the close position where the lid is fixed to the container body; releasing the lid by the clamp mechanisms; and lowering the support base from the operation region to the siding region.
According to a ninth aspect of the present invention, the method for opening and closing a lid of a transportation container as defined in the seventh aspect further comprises: the transportation mechanism is arranged between the operation region and the supply/discharge region, the transportation mechanism comprising a first guide member adapted to engage in the mounting base, and a first driver for use in sliding the mounting base horizontally in the longitudinal direction of the first guide member, the fixing mechanism for fixing the container body on the mounting base comprising a plurality of second drivers attached to the mounting base, and a plurality of fixing arms provided retractably on opposing sides of the mounting base, projected from the mounting base so as to clamp the sides of a lower part of the container body when the second drivers are operated.
According to a tenth aspect of the present invention, the method for opening and closing a lid of a transportation container as defined in the eighth aspect further comprises: the transportation mechanism is arranged between the operation region and the supply/discharge region, the transportation mechanism comprising a first guide member adapted to engage in the mounting base, and a first driver for use in sliding the mounting base horizontally in the longitudinal direction of the first guide member, the fixing mechanism for fixing the container body on the mounting base comprising a plurality of second drivers attached to the mounting base, and a plurality of fixing arms provided retractably on opposing sides of the mounting base, projected from the mounting base so as to clamp the sides of a lower part of the container body when the second drivers are operated.
According to an eleventh aspect of the present invention, the method for opening and closing a lid of a transportation container as defined in the seventh aspect further comprises: the lift mechanism is arranged between the operation region and the siding region, the lift mechanism comprising a second guide member adapted to guide the support base in vertical direction, and a third driver for use in moving up and down the support base in the longitudinal direction of the second guide member, the clamp mechanism comprising a plurality of fourth drivers attached to the support base via a standing member, and a plurality of clamp arms adapted to hold the sides of the lid when the fourth drivers are operated.
According to a twelfth aspect of the present invention, the method for opening and closing a lid of a transportation container as defined in the eighth aspect further comprises: the lift mechanism is arranged between the operation region and the siding region, the lift mechanism comprising a second guide member adapted to guide the support base in vertical direction, and a third driver for use in moving up and down the support base in the longitudinal direction of the second guide member, the clamp mechanism comprising a plurality of fourth drivers attached to the support base via a standing member, and a plurality of clamp arms adapted to hold the sides of the lid when the fourth drivers are operated.
According to a thirteenth aspect of the present invention, the method for opening and closing a lid of a transportation container as defined in the seventh aspect further comprises: the operation mechanism comprises a pair of third guide members with an approximately semi-circular cross section on opposing sides of the support base; a pair of sliding members slidably engaged with the third guide members, respectively, the sliding members moving close to and away from the periphery of the lid in response to the operation of a fifth driver; a plurality of presser arms attached to the sliding members, respectively, the presser arms move close to and away from the clamping pieces of the clamp plate in response to the operation of a sixth driver; and a plurality of operation arms attached to the sliding members, respectively, the operation arms move close to and away from the operated parts of the clamp plate in response to the operation of a seventh driver.
According to a fourteenth aspect of the present invention, the method for opening and closing a lid of a transportation container as defined in the eighth aspect further comprises: the operation mechanism comprises a pair of third guide members with an approximately semi-circular cross section on opposing sides of the support base; a pair of sliding members slidably engaged with the third guide members, respectively, the sliding members moving close to and away from the periphery of the lid in response to the operation of a fifth driver; a plurality of presser arms attached to the sliding members, respectively, the presser arms move close to and away from the clamping pieces of the clamp plate in response to the operation of a fifth driver; and a plurality of operation arms attached to the sliding members, respectively, the operation arms move close to and away from the operated parts of the clamp plate in response to the operation of a seventh driver.
According to the present invention, in order to engage the lid in the open front end of the container body of the transportation container and fix it therein, the lid is engaged and fixed in the open front end of the container body via the seal gasket for sealing and the clamp plates are moved toward each other by means of the operated parts in the direction of the opposing sides of the container body to close the clamp plates, thereby fitting the protrusions in the grooves and bending the holding pieces into the grooves to be clamped. The clamp plates are then clamped further by means of the operated parts in the direction of the opposing sides of the container body. The resultant elastic reaction force of the holding pieces provides fixation of the lid in the open front end of the container body.
On the other hand, in order to move the clamp plates to a release position where the lid can be removed that has been engaged with the open front end of the container body, the clamp plates are moved by means of the operated parts such that they swing to the release position from the opposing sides of the container body to separate the clamp plates from each other. Then, the holding pieces are bent and removed from the grooves to be clamped. This makes it possible to remove the lid engaged with the open front end of the container body.
In addition, according to the present invention, the clamp plates, the attachment shafts, the operated parts, and the holding pieces are integrally formed with predetermined synthetic resin, they can be mass-produced at a low cost. Furthermore, the flexibility and the elasticity can be provided with simple configuration and method. Moreover, the operated parts are formed to be bent toward either the top or the back surface of the clamp plates. This allows the arms and/or hooks for automatic operations to be contacted with the operated parts for engagement.
In addition, according to the present invention, in order to move the clamp plates such that the lid can be removed that has been engaged with the open front end of the container body of the transportation container, the seventh driver is operated to contact the operated parts of the clamp plates of the container body with the operation arms to engage them with each other. In this event, the holding pieces of the clamp plates are generally opposed to the pressing arms from the sides thereof. When the pressing arms are opposed to the holding pieces of the clamp plates, the sliding members are guided by the third guide member and away from the lid, along an approximately arc-shaped track. Then, the operation arms swing to a release position and the sixth driver is driven to contact strongly the pressing arms to the holding pieces of the clamp plates. The holding pieces are thus bent and away from the grooves to be clamped. The lid is now ready to be removed. The seventh driver is driven to separate the operation arms from the operated parts of the clamp plates.
On the other hand, in order to fix and secure the lid engaged with the open front end of the container body, the fifth driver is driven. The sliding members are guided by the third guide member and move closer to the lid along an approximately arc-shaped track. The clamp plates previously held by the operation arms swing to a close position and the sixth driver is driven to contact strongly the pressing arms to the holding pieces of the clamp plates. This results in bending of the holding pieces into the grooves to be clamped. As a result, the lid is fixed in the open front end of the container body. The seventh driver is driven to separate the operation arms from the operated parts of the clamp plates.